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Author Topic: Joule Thief  (Read 5875726 times)

Offline forest

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Re: Joule Thief
« Reply #16935 on: March 14, 2022, 08:38:09 PM »
is schematic the same or changed ?

Offline tysb3

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Re: Joule Thief
« Reply #16936 on: December 12, 2022, 01:52:44 AM »

Offline seychelles

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Re: Joule Thief
« Reply #16937 on: December 12, 2022, 09:43:33 AM »

Offline sm0ky2

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Re: Joule Thief
« Reply #16938 on: December 18, 2022, 12:46:51 PM »
All of this JT experimental data, leads us to question
certain aspects of battery tech.

Such as energy density, and of course the mAH ratings.

With the first, proclaiming to be the physics of the internal materials
and the latter being run-time tests performed by the manufacturers.

In both cases, the JT proves these values to be incorrect.

To put that in perspective: our tests begin AFTER the mAH has been consumed.
and most of the energy depleted, leaving theoretically low density values.
Yet the amount of energy obtained over long term led operations
can greatly exceed the expected values for both the remaining energy density,
as well as the total mAH available from the battery.

are we not fully understanding the factors we use to calculate energy density of a battery?
Are we underestimating the mAH rating by faulty testing? (or testing using limited device sets)

Or is there something deeper to be understood here?

I’m often left pondering the state of induction during the transistors ‘off’ time.
This is not often considered, because with the transistor ‘off’, the led is not being lit.
However, we know induction must be occurring, for the voltage to step up
enough to switch the transistor ‘on’.

Is it possible, that the induction during the off-cycle is causing a ‘reverse-charging’ scenario?
I.e. - drawing negative from the negative side of the source, thus (series) amplifying the voltage?

Adding a 3rd coil to the core gives an additional power output.
Now: if this is used directly, it affects the brightness (current) through the LED.
We experience a dimming effect when power is drawn from the 3rd coil.

However, if blocking diodes are used, DC pulses can be drawn out without affecting the led.
So is it the using of the power? Or the using of the inducing field, that takes from the circuit?

I tend to lean towards the latter, especially in cases where the power drawn out through the
3rd coil exceeds the theoretical values remaining in the (mostly dead) battery.

Example: when we max out the JT : meaning add series LED’s until the circuit cannot
light any additional series LEDs.
Using blocking diodes on the 3rd coil, we can further light many times the number of LED’s
as additional output from the 3rd coil.

Without the diodes in place, drawing from the 3rd coil drains power through the entire circuit.

If we isolate each half of the output cycle, we find that this killing effect occurs during
the forward pulse. But the reverse pulse seems to amplify the current through the first
2 (center tapped) coils. This is during the ‘off’ cycle!!! (amplified field collapse?)

I think Bill is correct in that the way this circuit is taught in schools, as well as how it
is USED in devices such as LED lightbulbs, AC-DC USB transformers, or even the
camera flash circuits: is an improper analysis.

The numbers come out in the math: voltage, inductance, change in voltage, change in current.
and the resulting changes in reluctance and impedance.

However, this makes no sense from the perspective of analyzing the source (battery).
Taking the negative voltage (field collapse) as a series voltage source works out a little closer,
however is still significantly off enough to assume we do not have all the data.

Offline tysb3

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Re: Joule Thief
« Reply #16939 on: December 18, 2022, 10:29:56 PM »
@ seychelles
replace bipolar transistor by mosfet and don't use ferrite ring. that's all about.